Movement of boron and fluoride from rod formations into Douglas-fir heartwood

Sections of Douglas-fir poles were used to assess the ability of boron and fluoride to diffuse from sodium fluoride and fluoride/boron rods. In general, chemical levels in the wood over the test period were below the threshold for inhibiting fungal attack regardless of the dosage, although acceptable levels were achieved in isolated locations in the pole sections. Higher dosages may be required to develop adequate chemical loadings in the wood, but the potential for weakening the poles by drilling additional treatment holes may outweigh any possible benefits of increasing the dosage